2007CBET.1152....1T

T. G. Tan, Mt. Claremont, Western Australia, reports the discovery of an apparent supernova on unfiltered CCD images taken on Nov. 7.52 UT with a 9.25-cm Celestron reflector, the new object reported as being located at R.A. = 1h49m52s.86, Decl. = -27o28'04".1 (equinox 2000.0; image scale 2"/pixel), or 14" east and 4" south of the nucleus of the galaxy NGC 689; galaxy light may have contaminated the magnitude measured for 2007rv, but a V-band image taken by Tan on Nov. 11.51 yielded mag 15.9 for the new object (unfiltered images taken by Tan on both nights showed a 0.9-mag brightening between the four nights). Digitized Sky Survey reference images were saturated at the location of 2007rv, and so additional confirmation was sought by the Central Bureau via its unconfirmed-objects webpage and via direct communication with numerous observers, including M. Suzuki (Utsunomiya, Tochigi, Japan), who obtained images remotely with a 0.25-m f/6 reflector at Moorook, Australia, on Nov. 23.650 and 24.495, measuring 2007rv to be V = 14.9 and 15.1, respectively, and having position end figures 52s.88 ± 0".02, 02".6 ± 0".1 (offset 15".2 east and 3".3 south of the nucleus of NGC 689). Suzuki adds that a USNO-B1.0-catalogue star (red mag 16.8) has position end figures 52s.79, 02".1. S. Nakano (Sumoto, Japan) reports that images taken by K. Nishiyama (Kurume, Fukuoka-ken, Japan), and F. Kabashima (Miyaki-cho, Saga-ken, Japan), presumably with a 40-cm f/9.8 reflector + unfiltered CCD, yield the following magnitudes for 2007rv: Nov. 7.52, 15.4; 28.563, 15.6; 29.607, 16.1. Nishiyama and Kabashima also provide the following position end figures from their images on Nov. 28 and 29: 52s.85 ± 0s.02, 02".2 ± 0".1